1. Field of the Invention
The present disclosure relates to an interlock apparatus of a vacuum circuit breaker, and particularly, to an interlock apparatus of a vacuum circuit breaker capable of preventing occurrence of an accident when an operator takes a circuit breaker main body from the interior of a cradle.
2. Background of the Invention
In general, a vacuum circuit breaker (VCB) is a circuit breaker for extinguishing an arc in a vacuum state, and is mainly used as a high voltage circuit breaker using high dielectric strength in a vacuum state.
Vacuum circuit breakers have a short circuit breaking time, have breaking performance not affected by a frequency, are low-noise type breakers without explosion when manipulated, and do not use oil, reducing fire hazard.
Also, vacuum circuit breakers may be manufactured to have a small size and have a simple structure, facilitating maintenance, and recently, 22.9 kV class vacuum circuit breakers are commonly used.
Vacuum circuit beakers are classified as a fixed type vacuum circuit breaker and a drawer type vacuum circuit breaker, and the drawer type circuit breaker includes a circuit breaker main body and a cradle.
According to a degree to which a circuit breaker main body is drawn in or drawn out from the cradle, the drawer type circuit breaker may be in a disconnected position in which both a main circuit and a control circuit are separated, a test position in which the main circuit is separated and the control circuit is connected, and a connected position in which both the main circuit and the control circuit are connected.
FIG. 1 is a view schematically illustrating an internal configuration of a vacuum circuit breaker in a connected position. FIG. 2 is a view schematically illustrating an internal configuration of the vacuum circuit breaker in a test position, and FIG. 3 is a view schematically illustrating an internal configuration of the vacuum circuit beaker in a disconnected position.
As illustrated in FIGS. 1 through 3, the vacuum circuit beaker includes a cradle 40 to which a door 10 is coupled, a truck 30 in which a circuit breaker main body 20 is installed, and the circuit breaker main body 20 installed in the truck 30 and moving within the cradle 40.
The cradle 40 provides a space allowing the truck 30 with the circuit breaker main body 20 loaded on an upper portion thereof to move in a forward/backward direction therein, and the circuit breaker main body 20, in a state of being loaded on the upper portion of the truck 30, moves in the forward/backward direction within the cradle 40 so as to be coupled to or separated from a terminal 41 formed within the cradle 40, thus applying or cutting off a current.
In the related art circuit breaker configured as described above, in the test position, the circuit breaker main body 20 positioned on the upper portion of the truck 30 is separated from the terminal 41 provided within the cradle 40, cutting off application of a current, and in the connected position, the truck 30 moves to the interior of the cradle 40 so as to be coupled to the terminal 41 within the cradle 40, and thus, a current is applied.
However, in a case in which the circuit breaker main body 20 is drawn out from the cradle 40, for replacement thereof, in the test position, since a device for supporting the circuit breaker main body 20 is not provided outside of the cradle 40, the drawn-out circuit breaker main body 20 may fall to lead to a high possibility that an operator may be physically damaged.
Also, when the circuit breaker main body 20 falls to be damaged, the circuit breaker main body 20 should be replaced with a new one, significantly increasing cost.